Human HSP27 is phosphorylated at serines 78 and 82 by heat shock and mitogen-activated kinases that recognize the same amino acid motif as S6 kinase II.
Human HSP27 is phosphorylated at serines 78 and 82 by heat shock and mitogen-activated kinases that recognize the same amino acid motif as S6 kinase II.
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DOI：
10.1016/s0021-9258(18)48354-8
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发表时间：
1992-01
期刊：
影响因子：
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通讯作者：
J. Landry;H. Lambert;Ming Zhou;J. Lavoie;E. Hickey;L. Weber;C. Anderson
中科院分区：
文献类型：
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作者：
J. Landry;H. Lambert;Ming Zhou;J. Lavoie;E. Hickey;L. Weber;C. Anderson
27 kDa的哺乳动物热休克蛋白（HSP 27）的细胞内浓度在热和其他代谢应激后增加数倍，并与获得耐热性密切相关。翻译后修饰也可能影响HSP 27的功能。热休克的HeLa细胞培养物，或处理亚砷酸盐，佛波酯，或肿瘤坏死因子，引起快速磷酸化的预先存在的HSP 27和三个磷酸化亚型，HSP 27 B，C和D的外观。用胰蛋白酶消化和通过反相高效液相色谱分离的肽显示三个32 P-标记的磷酸肽。微序列分析鉴定了峰I为Ala 76-Leu 77-Ser 78-Arg 79，峰II为Gln 80-Leu 81-Ser 82-Ser 83-Gly 84-Val 85-Ser 86-Glu 87-Ile 88-Arg 89;峰III含有未消化的肽对Ala 76-Arg 89。Ser 82是主要的磷酸化位点，Ser 78是次要的磷酸化位点。突变蛋白与丝氨酸78或丝氨酸82改变为甘氨酸或丝氨酸78-丝氨酸82双突变体的磷酸化，以减少在体内热或亚砷酸盐处理后的程度。Ser 78和Ser 82（和Ser 15）出现在序列基序RXXS中，其被核糖体蛋白S6激酶II识别。有丝分裂刺激血清剥夺，去逮捕中国仓鼠细胞与血清，凝血酶，或成纤维细胞生长因子也刺激磷酸化HSP 27 Ser 78和Ser 82，有丝分裂刺激和热休克激活蛋白激酶活性磷酸化HSP 27和蛋白S6在体外。这些结果表明，HSP 27可能在未应激细胞中发挥与生长信号通路相关的磷酸化激活功能。在这个水平上的稳态功能可以保护细胞免受在应激期间可能被不适当地激活的信号转导系统的不利影响。
The intracellular concentration of the 27-kDa mammalian heat shock protein, HSP27, increases several-fold after heat and other metabolic stresses and is closely associated with the acquisition of thermotolerance. Posttranslational modifications may also affect the function of HSP27. Heat shock of HeLa cell cultures, or treatment with arsenite, phorbol ester, or tumor necrosis factor, caused a rapid phosphorylation of preexisting HSP27 and the appearance of three phosphorylated isoforms, HSP27 B, C, and D. Digestion with trypsin and fractionation of the peptides by reverse phase high performance liquid chromatography revealed three 32P-labeled phosphopeptides. Microsequence analysis identified peak I as Ala76-Leu77-Ser78-Arg79 and peak II as Gln80-Leu81-Ser82-Ser83-Gly84-Val85- Ser86-Glu87-Ile88-Arg89; peak III contained the undigested peptide pair Ala76-Arg89. Ser82 was the major site and Ser78 the minor site of phosphorylation. Mutant proteins with Ser78 or Ser82 altered to glycine or Ser78-Ser82 double mutants were phosphorylated to reduced extents in vivo after heat or arsenite treatment. Ser78 and Ser82 (and Ser15) occur in the sequence motif RXXS, which is recognized by ribosomal protein S6 kinase II. Mitogenic stimulation of serum-deprived, Go-arrested Chinese hamster cells with serum, thrombin, or fibroblast growth factor also stimulated phosphorylation of HSP27 Ser78 and Ser82, and mitogenic stimulation and heat shock activated protein kinase activities that phosphorylated HSP27 and protein S6 in vitro. These results suggest that HSP27 may exert phosphorylation-activated functions linked with growth signaling pathways in unstressed cells. A homeostatic function at this level could protect cells from adverse effects of signal transduction systems which may be activated inappropriately during stress.